1. Fields of the Invention
The present invention relates to a ceiling fan, and more particularly, to a folding and unfolding structure of blades of a ceiling fan. The blades are folded when not in operation, and unfolded when in use.
2. Descriptions of Related Art
The conventional ceiling fans are cataloged into fixed type and expanding type. The fixed type means that the blades are fixed to the rotary member and always in expanded status. The expanding type means that the blades are pivotably connected to the rotary member which is connected to the motor. When the ceiling fan is not in use, the blades are folded inward. When the ceiling fan is in operation, the blades unfold outward when the rotary member rotates.
There are two different operational types for the expanding type ceiling fans. The first one is that the blades unfold horizontally relative to the rotary member, and unfold inward. The mechanism for the first one operational type includes a main gear cooperated with planet gears to allow the blades to fold by resilient members, and to unfold due to eccentric force when the rotary member rotates. Taiwan patent number M345145, M387920 and M482700 respectively disclose such types of ceilings.
The second one is that the blades are folded downward when not in use such as those disclosed by Taiwan patent number M244370, and China Patent number ZL 200620115610.7. The blades are pivotably connected to the rotary member by support arms pivotably connected between the blades and the rotary member. When the ceiling fan is not in use, the blades are folded and extend downward and are located around the rotary member. This type is easily to clean up when compared with the first type that the blades may be damaged when being cleaned up. However, when in operation, the support arms pivot up and down so that the motor has to overcome the weight of the blade and the length of the arm of force of the support arms, therefore, the motor bears a heavy load and is easily shank and vibrate.
The present invention intends to provide a folding and unfolding structure for blades of a ceiling fan to eliminate the drawbacks mentioned above.